The present invention relates to a wideband Gbyte Gbps communication system, and more particularly, to an apparatus and method for ray-tracing in a wideband Gbyte Gbps communication system which can improve accuracy of ray-tracing by considering physical characteristics of a reflection plane in the wideband Gbyte Gbps communication system.
For a conventional communication system, the maximum amount of data transfer is a few megabytes, and a data transfer rate of several Mbps is also sufficient. However, due to the recent trends for diversification, upgrading and enlarging content capacity, conventional communication systems are hard-pressed to cope with these trends, where data capacity of 1 Gbyte or more and high transfer rates of 1 Gbps or more are required.
In order to establish such communication system, development of communication systems and research on the frequency bands of millimeter waves or greater are currently in progress, and communication industries are now developing communication systems for 60 GHz and 70/80 GHz bands.
Conventionally, since the length of wavelength is very short in the case of a millimeter wave band signal, there are limitations in analyzing this signal with existing propagation models and estimation methods.
When a radio wave is transferred through a line of sight path, a propagation path of the radio wave maintains a direct path, and signal strength may be represented as an attenuation function of frequency depending on distance. When an obstacle exists between a transmitter and a receiver, a propagation path of a signal is determined by the sequence of transmitter-obstacle-receiver such that the signal strength arriving at the receiver is determined by factoring in a reflection coefficient, in which electrical characteristics of a medium of the obstacle are reflected, in a frequency function depending on distance.
At this time, the signal strength due to the obstacle is determined by multiplying the reflection coefficient, in which permittivity and conductivity, electrical characteristics of the medium of the obstacle, are reflected in the direction of a reflected angle having the same magnitude as an incident angle according to Snell's law (assuming that the surface of the obstacle is a smooth one) to an attenuation amplitude due to the propagation path.
However, if it could be assumed in conventional communication systems of a few hundred MHz and a few GHz that the reflection plane of the obstacle is smooth, when the frequency is increased to a few tens GHz or more, a wavelength of the signal will be shortened to a millimeter wave or less such that the obstacle can no longer be assumed to be smooth, as in the related art. This is because the radio waves react more sensitively on the surface of the reflection plane in the case of the millimeter wave band unlike in the conventional case.
FIG. 1 illustrates a diagram of a reflection path of a radio wave according to the Snell's law.
FIG. 1 illustrates a process in which the radio wave coming from a transmitter TX is transferred to a receiver RX after reflecting from an obstacle 3 according to the Snell's law.
When a signal started from the transmitter TX is reflected at the obstacle 3 to arrive at the receiver RX in a conventional ray-tracing method, the reflection occurs with the same magnitude of angle (<a=<b) as an incident angle (<a) on the basis of a normal vector n of a reflection plane. After multiplying a reflection coefficient (┌) to a path loss as much as a length of an incident path R1, a path loss as much as a length of a reflection path R2 is transferred to the receiver RX as a signal amplitude.
However, since it is assumed that the obstacle is always in a state of a perfectly flat plane according to this method, there is a limitation to analyze frequency bands of the millimeter wave or more.
Because, although the surface of a wall looks smooth in a real environment, many tiny irregularities constitute a rough surface if we look at the surface of a wall more closely. Therefore, if the propagation path is transmitter-obstacle-receiver, there is a problem of increasing estimation errors when simply applying the Snell's law.
The foregoing technical configuration is only provided as a background technology for helping to understand the present invention and does not mean the related art widely known in the art to which the present invention pertains.